Preheat oven to 350 degrees F. Line a baking sheet with parchment paper. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, sugar, brown sugar, peanut butter, and egg together until fluffy.

Slowly add the dry ingredients to wet mixture, beating until well blended. Fold in the M&M's candies.

Drop a tablespoon of dough onto the prepared baking sheet. Roll into a ball. Bake 12 minutes until lightly browned.

Remove cookies to a cooling rack. Let cool completely.

Melt the red candy melts as directed on the package. Drizzle over the cookies with the end of a knife to make blood splatter. Let dry before serving.